144 



MARSUPIALIA 



the fourth ; the fifth somewhat shorter. Tail not quite so long as 

 the body, and covered with short hairs forming a slight crest. Ears 

 large and pointed, and folded down when the animal 

 is at rest. Fur soft and loose. Vertebrae : C 7, D 

 13, L 6, S 1, C 20. Skull short and wide, with a 

 small and single bulla, and a contraction of the 

 muzzle at the third premolar. 



The only known species of this genus (Fig. 44), 

 chiefly remarkable for the singular construction of 

 its limbs, is an animal about the size of a small 

 Rat, found in the interior of the Australian continent. 

 Its general habits and food appear to resemble those 

 of the other Peramelidce. It was first described as 

 C. ecaiidatus by Ogilby from a mutilated specimen, 

 but the specific name was afterwards changed, as being 

 inappropriate, by Gray to castanotis. 



Suborder DIPROTODONTIA. 



For the leading characters of this group, see 

 page 132. 



PIG. 43. Skele- 

 ton of right hind 

 foot of Chccropus 

 castanotis. c, Cal- 

 caneum ; a, astra- 

 galus ; c6, cuboid ; 

 n, navicular ; c3, 

 ectocuneiform ; II 

 and III, the con- 

 joined second end 

 third digits ; IV, 

 the large and only 

 functional digit ; 

 V, the rudiment- 

 ary fifth digit. 



Family PHASCOLOMYID^E 



Dentition : c *-, i ft, p \, m % = 24. All the teeth 

 with persistent pulps. The incisors large, scalpriform, 

 with enamel only on the front surface, as in the 

 Rodentia. The molars strongly curved, forming from 

 the base to the summit about a quarter of a circle, 

 the concavity being directed outwards in the upper 

 and inwards in the lower teeth. The first of the 

 series, or premolar, appears to have no milk-prede- 

 cessor, and is single-lobed ; the other four composed 

 of two lobes, each subtriangular in section. Limbs 

 equal, stout, and short. Fore feet with five distinct toes, each 

 furnished with a long, strong, and slightly curved nail, the first and 

 fifth considerably shorter than the other three. Hind feet with a very 

 short nailless hallux, the second, third, and fourth toes partially 

 united by integument, of nearly equal length, the fifth distinct 

 and rather shorter ; all four provided with long and curved nails. 

 In the skeleton of the foot, the second and third toes are distinctly 

 more slender than the fourth, showing a slight tendency towards 

 the peculiar character so marked in the next two families. Tail 

 rudimentary. Stomach simple, provided with a special gland 

 situated near the cardiac orifice. Caecum very short, wide, and with 

 a peculiar vermiform appendage. Pouch present. The auditory 

 bullae of the skull are imperfect, open behind, with their anterior 



